/*
 * This file is part of the OregonCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "MapTree.h"
#include "Models/ModelInstance.h"
#include "Management/VMapManager2.h"
#include "VMapDefinitions.h"

#include <string>
#include <sstream>
#include <iomanip>
#include <limits>

#ifndef NO_CORE_FUNCS
    #include "Errors.h"
#else
    #define ASSERT(x)
#endif

using G3D::Vector3;

namespace VMAP
{

class MapRayCallback
{
    public:
        MapRayCallback(ModelInstance* val): prims(val), hit(false) {}
        bool operator()(const G3D::Ray& ray, uint32 entry, float& distance, bool pStopAtFirstHit = true)
        {
            bool result = prims[entry].intersectRay(ray, distance, pStopAtFirstHit);
            if (result)
                hit = true;
            return result;
        }
        bool didHit() { return hit; }
    protected:
        ModelInstance* prims;
        bool hit;
};

class AreaInfoCallback
{
    public:
        AreaInfoCallback(ModelInstance* val): prims(val) {}
        void operator()(const Vector3& point, uint32 entry)
        {
            #ifdef VMAP_DEBUG
                DEBUG_LOG("AreaInfoCallback: trying to intersect '%s'", prims[entry].name.c_str());
            #endif
            prims[entry].intersectPoint(point, aInfo);
        }

        ModelInstance* prims;
        AreaInfo aInfo;
};

class LocationInfoCallback
{
    public:
        LocationInfoCallback(ModelInstance* val, LocationInfo& info): prims(val), locInfo(info), result(false) {}
        void operator()(const Vector3& point, uint32 entry)
        {
            #ifdef VMAP_DEBUG
                DEBUG_LOG("LocationInfoCallback: trying to intersect '%s'", prims[entry].name.c_str());
            #endif
            if (prims[entry].GetLocationInfo(point, locInfo))
                result = true;
        }

        ModelInstance* prims;
        LocationInfo& locInfo;
        bool result;
};

//=========================================================

std::string StaticMapTree::getTileFileName(uint32 mapID, uint32 tileX, uint32 tileY)
{
    std::stringstream tilefilename;
    tilefilename.fill('0');
    tilefilename << std::setw(3) << mapID << '_';
    //tilefilename << std::setw(2) << tileX << '_' << std::setw(2) << tileY << ".vmtile";
    tilefilename << std::setw(2) << tileY << '_' << std::setw(2) << tileX << ".vmtile";
    return tilefilename.str();
}

bool StaticMapTree::getAreaInfo(Vector3& pos, uint32& flags, int32& adtId, int32& rootId, int32& groupId) const
{
    AreaInfoCallback intersectionCallBack(iTreeValues);
    iTree.intersectPoint(pos, intersectionCallBack);
    if (intersectionCallBack.aInfo.result)
    {
        flags = intersectionCallBack.aInfo.flags;
        adtId = intersectionCallBack.aInfo.adtId;
        rootId = intersectionCallBack.aInfo.rootId;
        groupId = intersectionCallBack.aInfo.groupId;
        pos.z = intersectionCallBack.aInfo.ground_Z;
        return true;
    }
    return false;
}

bool StaticMapTree::GetLocationInfo(const Vector3& pos, LocationInfo& info) const
{
    LocationInfoCallback intersectionCallBack(iTreeValues, info);
    iTree.intersectPoint(pos, intersectionCallBack);
    return intersectionCallBack.result;
}

StaticMapTree::StaticMapTree(uint32 mapID, const std::string& basePath):
    iMapID(mapID), iTreeValues(0), iBasePath(basePath)
{
        if (iBasePath.length() > 0 && iBasePath[iBasePath.length()-1] != '/' && iBasePath[iBasePath.length()-1] != '\\')
            iBasePath.push_back('/');
}

//=========================================================
//! Make sure to call unloadMap() to unregister acquired model references before destroying
StaticMapTree::~StaticMapTree()
{
    delete[] iTreeValues;
}

//=========================================================
/**
If intersection is found within pMaxDist, sets pMaxDist to intersection distance and returns true.
Else, pMaxDist is not modified and returns false;
*/

bool StaticMapTree::getIntersectionTime(const G3D::Ray& pRay, float& pMaxDist, bool pStopAtFirstHit) const
{
    float distance = pMaxDist;
    MapRayCallback intersectionCallBack(iTreeValues);
    iTree.intersectRay(pRay, intersectionCallBack, distance, pStopAtFirstHit);
    if (intersectionCallBack.didHit())
        pMaxDist = distance;
    return intersectionCallBack.didHit();
}
//=========================================================

bool StaticMapTree::isInLineOfSight(const Vector3& pos1, const Vector3& pos2) const
{
    float maxDist = (pos2 - pos1).magnitude();
        // return false if distance is over max float, in case of cheater teleporting to the end of the universe
        if (maxDist == std::numeric_limits<float>::max() || !std::isfinite(maxDist))
            return false;

    // valid map coords should *never ever* produce float overflow, but this would produce NaNs too
    ASSERT(maxDist < std::numeric_limits<float>::max());
    // prevent NaN values which can cause BIH intersection to enter infinite loop
    if (maxDist < 1e-10f)
        return true;
    // direction with length of 1
    G3D::Ray ray = G3D::Ray::fromOriginAndDirection(pos1, (pos2 - pos1) / maxDist);
    if (getIntersectionTime(ray, maxDist, true))
        return false;

    return true;
}

//=========================================================
/**
When moving from pos1 to pos2 check if we hit an object. Return true and the position if we hit one
Return the hit pos or the original dest pos
*/
bool StaticMapTree::getObjectHitPos(const Vector3& pPos1, const Vector3& pPos2, Vector3& pResultHitPos, float pModifyDist) const
{
    bool result = false;
    float maxDist = (pPos2 - pPos1).magnitude();
    // valid map coords should *never ever* produce float overflow, but this would produce NaNs too
    ASSERT(maxDist < std::numeric_limits<float>::max());
    // prevent NaN values which can cause BIH intersection to enter infinite loop
    if (maxDist < 1e-10f)
    {
        pResultHitPos = pPos2;
        return false;
    }
    Vector3 dir = (pPos2 - pPos1) / maxDist;            // direction with length of 1
    G3D::Ray ray(pPos1, dir);
    float dist = maxDist;
    if (getIntersectionTime(ray, dist, false))
    {
        pResultHitPos = pPos1 + dir * dist;
        if (pModifyDist < 0)
        {
            if ((pResultHitPos - pPos1).magnitude() > -pModifyDist)
                pResultHitPos = pResultHitPos + dir * pModifyDist;
            else
                pResultHitPos = pPos1;
        }
        else
            pResultHitPos = pResultHitPos + dir * pModifyDist;

        result = true;
    }
    else
    {
        pResultHitPos = pPos2;
        result = false;
    }
    return result;
}

//=========================================================

float StaticMapTree::getHeight(const Vector3& pPos, float maxSearchDist) const
{
    float height = G3D::inf();
    Vector3 dir = Vector3(0, 0, -1);
    G3D::Ray ray(pPos, dir);   // direction with length of 1
    float maxDist = maxSearchDist;
    if (getIntersectionTime(ray, maxDist, false))
        height = pPos.z - maxDist;

    return (height);
}

//=========================================================

bool StaticMapTree::CanLoadMap(const std::string& vmapPath, uint32 mapID, uint32 tileX, uint32 tileY)
{
    std::string basePath = vmapPath;
    if (basePath.length() > 0 && basePath[basePath.length()-1] != '/' && basePath[basePath.length()-1] != '\\')
        basePath.push_back('/');
    std::string fullname = basePath + VMapManager2::getMapFileName(mapID);
    bool success = true;
    FILE* rf = fopen(fullname.c_str(), "rb");
    if (!rf)
        return false;
    // @todo: check magic number when implemented...
    char tiled;
    char chunk[8];
    if (!readChunk(rf, chunk, VMAP_MAGIC, 8) || fread(&tiled, sizeof(char), 1, rf) != 1)
    {
        fclose(rf);
        return false;
    }
    if (tiled)
    {
        std::string tilefile = basePath + getTileFileName(mapID, tileX, tileY);
        FILE* tf = fopen(tilefile.c_str(), "rb");
        if (!tf)
            success = false;
        else
        {
            if (!readChunk(tf, chunk, VMAP_MAGIC, 8))
                success = false;
            fclose(tf);
        }
    }
    fclose(rf);
    return success;
}

    //=========================================================

bool StaticMapTree::InitMap(const std::string& fname, VMapManager2* vm)
{
    DEBUG_LOG("StaticMapTree::InitMap() : initializing StaticMapTree '%s'", fname.c_str());
    bool success = true;
    std::string fullname = iBasePath + fname;
    FILE* rf = fopen(fullname.c_str(), "rb");
    if (!rf)
        return false;
    else
    {
        char chunk[8];
        //general info
        if (!readChunk(rf, chunk, VMAP_MAGIC, 8)) success = false;
            char tiled = '\0';
        if (success && fread(&tiled, sizeof(char), 1, rf) != 1) success = false;
        iIsTiled = bool(tiled);
        // Nodes
        if (success && !readChunk(rf, chunk, "NODE", 4)) success = false;
        if (success) success = iTree.readFromFile(rf);
        if (success)
        {
            iNTreeValues = iTree.primCount();
            iTreeValues = new ModelInstance[iNTreeValues];
        }

        if (success && !readChunk(rf, chunk, "GOBJ", 4)) success = false;
        // global model spawns
        // only non-tiled maps have them, and if so exactly one (so far at least...)
        ModelSpawn spawn;
        #ifdef VMAP_DEBUG
            DEBUG_LOG("StaticMapTree::InitMap() : map isTiled: %u", static_cast<uint32>(iIsTiled));
        #endif
        if (!iIsTiled && ModelSpawn::readFromFile(rf, spawn))
        {
            WorldModel* model = vm->acquireModelInstance(iBasePath, spawn.name);
            DEBUG_LOG("StaticMapTree::InitMap(): loading %s", spawn.name.c_str());
            if (model)
            {
                // assume that global model always is the first and only tree value (could be improved...)
                iTreeValues[0] = ModelInstance(spawn, model);
                iLoadedSpawns[0] = 1;
            }
            else
            {
                success = false;
                ERROR_LOG("StaticMapTree::InitMap() : could not acquire WorldModel pointer for '%s'", spawn.name.c_str());
            }
        }

        fclose(rf);
    }
    return success;
}

    //=========================================================

void StaticMapTree::UnloadMap(VMapManager2* vm)
{
    for (loadedSpawnMap::iterator i = iLoadedSpawns.begin(); i != iLoadedSpawns.end(); ++i)
    {
        iTreeValues[i->first].setUnloaded();
        for (uint32 refCount = 0; refCount < i->second; ++refCount)
            vm->releaseModelInstance(iTreeValues[i->first].name);
    }
    iLoadedSpawns.clear();
    iLoadedTiles.clear();
}

    //=========================================================

bool StaticMapTree::LoadMapTile(uint32 tileX, uint32 tileY, VMapManager2* vm)
{
    if (!iIsTiled)
    {
        // currently, core creates grids for all maps, whether it has terrain tiles or not
        // so we need "fake" tile loads to know when we can unload map geometry
        iLoadedTiles[packTileID(tileX, tileY)] = false;
        return true;
    }
    if (!iTreeValues)
    {
        ERROR_LOG("StaticMapTree::LoadMapTile() : tree has not been initialized [%u, %u]", tileX, tileY);
        return false;
    }
    bool result = true;

    std::string tilefile = iBasePath + getTileFileName(iMapID, tileX, tileY);
    FILE* tf = fopen(tilefile.c_str(), "rb");
    if (tf)
    {
        char chunk[8];

        if (!readChunk(tf, chunk, VMAP_MAGIC, 8))
            result = false;
        uint32 numSpawns = 0;
        if (result && fread(&numSpawns, sizeof(uint32), 1, tf) != 1)
            result = false;
        for (uint32 i = 0; i < numSpawns && result; ++i)
        {
            // read model spawns
            ModelSpawn spawn;
            result = ModelSpawn::readFromFile(tf, spawn);
            if (result)
            {
                // acquire model instance
                WorldModel* model = vm->acquireModelInstance(iBasePath, spawn.name);
                if (!model)
                        ERROR_LOG("StaticMapTree::LoadMapTile() : could not acquire WorldModel pointer [%u, %u]", tileX, tileY);

                // update tree
                uint32 referencedVal;

                if (fread(&referencedVal, sizeof(uint32), 1, tf) == 1)
                {
                    if (!iLoadedSpawns.count(referencedVal))
                    {
                        if (referencedVal > iNTreeValues)
                        {
                            ERROR_LOG("StaticMapTree::LoadMapTile() : invalid tree element (%u/%u) referenced in tile %s", referencedVal, iNTreeValues, tilefile.c_str());
                            continue;
                        }
                        iTreeValues[referencedVal] = ModelInstance(spawn, model);
                        iLoadedSpawns[referencedVal] = 1;
                    }
                    else
                    {
                        ++iLoadedSpawns[referencedVal];
                        #ifdef VMAP_DEBUG
                        if (iTreeValues[referencedVal].ID != spawn.ID)
                            DEBUG_LOG("StaticMapTree::LoadMapTile() : trying to load wrong spawn in node");
                        else if (iTreeValues[referencedVal].name != spawn.name)
                            DEBUG_LOG("StaticMapTree::LoadMapTile() : name collision on GUID=%u", spawn.ID);
                        #endif
                    }
                }
                else
                    result = false;
            }
        }
        iLoadedTiles[packTileID(tileX, tileY)] = true;
        fclose(tf);
    }
    else
        iLoadedTiles[packTileID(tileX, tileY)] = false;

    return result;
}

    //=========================================================

void StaticMapTree::UnloadMapTile(uint32 tileX, uint32 tileY, VMapManager2* vm)
{
    uint32 tileID = packTileID(tileX, tileY);
    loadedTileMap::iterator tile = iLoadedTiles.find(tileID);
    if (tile == iLoadedTiles.end())
    {
        ERROR_LOG("StaticMapTree::UnloadMapTile() : trying to unload non-loaded tile - Map:%u X:%u Y:%u", iMapID, tileX, tileY);
        return;
    }
    if (tile->second) // file associated with tile
    {
        std::string tilefile = iBasePath + getTileFileName(iMapID, tileX, tileY);
        FILE* tf = fopen(tilefile.c_str(), "rb");
        if (tf)
        {
            bool result = true;
            char chunk[8];
            if (!readChunk(tf, chunk, VMAP_MAGIC, 8))
                result = false;
            uint32 numSpawns;
            if (fread(&numSpawns, sizeof(uint32), 1, tf) != 1)
                result = false;
            for (uint32 i = 0; i < numSpawns && result; ++i)
            {
                // read model spawns
                ModelSpawn spawn;
                result = ModelSpawn::readFromFile(tf, spawn);
                if (result)
                {
                    // release model instance
                    vm->releaseModelInstance(spawn.name);

                    // update tree
                    uint32 referencedNode;

                    if (fread(&referencedNode, sizeof(uint32), 1, tf) != 1)
                        result = false;
                    else
                    {
                        if (!iLoadedSpawns.count(referencedNode))
                            ERROR_LOG("StaticMapTree::UnloadMapTile() : trying to unload non-referenced model '%s' (ID:%u)", spawn.name.c_str(), spawn.ID);
                        else if (--iLoadedSpawns[referencedNode] == 0)
                        {
                        iTreeValues[referencedNode].setUnloaded();
                        iLoadedSpawns.erase(referencedNode);
                        }
                    }
                }
            }
            fclose(tf);
        }
    }
    iLoadedTiles.erase(tile);
}

}
